This invention relates to a vehicle-borne spray boom for wide pattern application of a liquid chemical to the grounds of a golf course or the like.
Vehicle-borne spray booms are commonly used in agricultural and commercial applications for applying liquid chemicals such as fertilizer, herbicide or insecticide over an expansive area such as a field, park, golf course, etc. The liquid chemical is typically stored in a tank carried or towed by the tractor, and is dispense through an array of spray nozzles distributed along the length of the spray boom. The boom is generally is generally provided with a mounting plate at its midpoint, and the boom arms are laterally cantilevered from the mounting plate. Also, the boom arms are commonly divided into sections that are hinged and foldable for ease of transportation and storage.
Spray booms of the type described above are obviously best suited for use on relatively flat terrain so that a generally consistent distance is maintained between the ground and the spray nozzles, ensuring even application of the liquid chemical. However, flat terrain is frequently not the norm in parks and golf courses, resulting in uneven application of the liquid chemical, and in some cases, interference between the ground and the boom. These disadvantages can be avoided to some extent by elevating the entire boom, but elevating the boom makes the spray pattern more susceptible to wind effects, and optimal application of a liquid chemical is usually achieved when the spray nozzle is maintained within about 12-24 inches of the ground surface, depending on the nozzle design. Accordingly, what is needed is a spray boom that retains the advantages of currently known devices, but which is capable of maintaining a consistent and optimal distance between the spray nozzles and the ground on hilly and uneven terrain.
The present invention is directed to an improved vehicle-borne spray boom apparatus having multiple articulated sections that are foldable and individually supported with respect to the ground to maintain a consistent and optimal distance between the boom sections and the ground on hilly and uneven terrain. A center section of the boom is mounted on a forward facing frame element of the vehicle, and boom arms extending from either end of the center section each comprise at least first and second sections, each supported by a ground-engaging wheel. Each first section is coupled at one end to the center section to permit vertical inclination with respect to the center section, and each second section is coupled at one end to a respective first section to permit vertical inclination with respect to such first section. The coupling between the central and first sections additionally permits relative horizontal inclination, and releasable latch mechanisms are triggered upon full horizontal extension of the first sections to maintain a proper alignment between the first and center sections. In a preferred implementation, each of the second sections includes a tip portion (or third section) that is hinged to permit rearward horizontal inclination with respect to the remainder of the second section and a spring coupling for biasing the tip portion into alignment with the second section.